The present invention relates to a serial recording apparatus that detects the amount of sheet feed each time the sheet is fed, determines a print area in accordance with each of the amount of sheet feed thus detected, and carries out the printing with respect to the print area thus determined so as to dissolve the inadequate printing.
For example, Japanese unexamined patent publication No. 5-147278 (publication date: Jun. 15, 1993) discloses the relation between the amount of sheet feed and a print area in a conventional serial printer. Such a serial printer is provided with (a) means for setting the amount of sheet feed provided that the amount of sheet feed is fixed, and (b) means for controlling the amount of sheet feed. In this case, the print area is fixed so as to correspond to a single amount of sheet feed.
According to U.S. Pat. No. 5,603,578 (issue date: Feb. 18, 1997), proposed is a method in which the amount of sheet feed is fixed, zero is written in an area sticking out the sheet so as not to jet the ink.
According to Japanese unexamined patent publication No. 8-132679 (publication date: May 28, 1996), proposed is a method in which, prior to the printing, images are overlapped so that a white line does not appear in a main scanning direction.
However, according to each of the conventional arts advance steps are prepared and made so that the amount of sheet feed is kept to be uniform. Accordingly, no posterior steps are made with respect to the inevitable fact that the amount of sheet feed is not uniform.
Even in the advance above-mentioned steps, the following problems arise. More specifically, in the case where the amount of sheet feed changes due to the change in the feed load in the feeding system in accordance with the kinds of the sheet such as size, thickness, and smoothness, it is most likely that a white line appears in the joint portion of the images when the amount of sheet feed is too much. In contrast, the slipping off of the printing due to such as the occurrence of a double printing in the joint portion of the images when the amount of sheet feed is too little.
The present invention is made in view of the foregoing problems, and its object is to dissolve the inadequate printing by detecting the amount of sheet feed each time the sheet is fed, determining a print area in accordance with each of the amount of sheet feed thus detected, and carrying out the printing with respect to the print area thus determined.
In order to achieve the foregoing object, a serial recording apparatus in accordance with the present invention is provided with at least one recording means for jetting visualizing agent such as ink toward a recording medium such as a sheet via a plurality of jet sections such as nozzles, in which information corresponding to 1 line is recorded (printed) to the recording medium while the recording medium is fed and scanned in a first direction, and feed means such as a sheet feed roller and an idler roller feeds the recording medium in a second direction, is characterized by further comprising the following means.
More specifically, the serial recording apparatus further comprises (a) feed amount detection means such as encoder for detecting feed amount of the recording medium by the feed means in the second direction after each scanning finishes, and (b) jet section selecting means such as a computer for selecting jet sections to be used for recording among the plurality of jet sections in accordance with the feed amount that has been detected by the feed amount detection means.
According to the invention, the visualizing agent is jetted toward the recording medium via the jet sections, while at least one recording means are fed and scanned in the first direction, thereby resulting in that the information corresponding to 1 line is recorded. When the information corresponding to 1 line is recorded, the recording medium is fed by the feed means in the second direction. Then, the information corresponding to the next line is recorded in a similar manner to the above-mentioned procedure. By repeating the procedure, the information is continuously recorded on a single recording medium.
It may happen that the feed amount of the recording medium is not coincident with the target amount due to some reasons, during the feeding of the recording medium in the second direction so as to record in the next line the information corresponding to the next line. Namely, the feed amount of the recording medium may become more or less than the ordinary (usual) amount. In this case, according to the conventional art, since all the jet sections are used so as to jet the visualizing agent, although the recording should have been carried out continuously, a vacant area occurs in the recording result when the feed amount is more than the ordinary amount while an overlapping area is occurs in the recording result when the feed amount is less than the ordinary amount. This causes the problem that the quality of the recording remarkably deteriorates.
In order to solve the problem, according to the present invention, the feed amount of the recording medium in the second direction is detected, and based on the feed amount that has been thus detected, the jet sections to be used for recording the information corresponding to the next line are selected among the plurality of jet sections. Accordingly, only the jet sections that has been thus selected jet the visualizing agent toward the recording medium.
More specifically, after the scanning of 1 line is carried out, the recording medium is fed in the second direction by the feed means. Thereafter, the scanning of the next line is carried out. The feed amount is detected by the feed amount detection means. Based on the feed amount that has been thus detected, the jet sections to be used for the recording of the next line are selected among the plurality of jet sections by the jet section selecting means. This allows to continuously record the information on the recording medium, even when the feed amount becomes more or less than the ordinary amount, without the vacant area and/or the overlapping area in the recording result, by changing the selection of the jet sections in the recording means that contributes to the recording. Therefore, it is possible to avoid that the inadequate recording occurs.
For example, when the recording medium is fed by the ordinary feed amount in the second direction, it is assumed that the visualizing agent is jetted toward the recording medium via a predetermined number of jet sections so as to carry out the recording of the information. When the recording medium is fed more than the ordinary amount in the second direction, jet sections on the upstream side in the second direction are selected more than usual in accordance with the feed amount that has been detected. Such jet sections contribute to the recording, so that it is possible to continuously record the information with respect to the area that will be the vacant area according to the conventional art.
In contrast, when the recording medium is fed less than the ordinary amount in the second direction, (a) jet sections on the downstream side in the second direction are selected more than usual in accordance with the feed amount that has been detected and (b) jet sections on the upstream side in the second direction are selected less than usual in accordance with the feed amount that has been detected. Such jet sections contribute to the recording, so that it is possible to record the information with respect to the area that will be the overlapping area according to the conventional art.
The following arrangement is preferable. More specifically, the recording means is provided with (a) a first area (Y1) in which a plurality of jet sections are provided in the vicinity of an end part of the recording means on the upstream side in the second direction, (b) a second area (Y2) in which a plurality of jet sections are provided in the vicinity of an end part of the recording means on the downstream side in the second direction, (c) a third area (Z), other than the first and second areas, in which a plurality of jet sections are provided. The jet section selecting means (1) selects all the jet sections in the third area when the recording medium is fed by the ordinary feed amount in the second direction, (2) selects the jet sections among the first through third areas in accordance with the feed amount that has been detected, when the recording medium is fed more than the ordinary amount in the second direction, and (3) selects the jet sections among the second and third areas in accordance with the feed amount that has been detected, when the recording medium is fed less than the ordinary amount in the second direction.
In this case, when the recording medium is fed by the ordinary feed amount in the second direction, all the jet sections in the third area are selected by the jet section selecting means. The visualizing agent is jetted toward the recording medium via the jet the sections that have been thus selected so as to record the information on the recording medium.
In the case where the recording medium is fed more than the ordinary amount in the second direction, when the recording is carried out in a similar manner to the ordinary case, it is most likely to occur a vacant area in the recording result. In order to meet the deficiency, according to the present invention, the jet sections are selected among the first through third areas by the jet section selecting means in accordance with the feed amount that has been detected. This allows (a) the jet sections in the area which is larger than usual to be selected and (b) the visualizing agent to jet toward the recording medium via the jet sections that have been thus selected so as to record the information on the recording medium. Accordingly, it is possible to continuously record the information with respect to the area that will be the vacant area according to the conventional art.
In the case where the recording medium is fed less than the ordinary amount in the second direction, when the recording is carried out in a similar manner to the ordinary case, it is most likely to occur an overlapping area in the recording result. In order to meet the deficiency, according to the present invention, the jet sections are selected among the second and third areas by the jet section selecting means in accordance with the feed amount that has been detected. In this case, when jet sections on the upstream side of the third area in the second direction are not selected in accordance with the required number, the jet sections that have not been thus selected do not contribute to the recording. The visualizing agent is jetted toward the recording medium via the jet sections that have been selected so as to record the information, so that it is possible to continuously record the information with respect to the area that will be the overlapping area according to the conventional art.
Some feed amount allows to record the information with the same recording width (the width in the second direction) as the ordinary recording, by selecting the jet sections in the areas other than the area of the ordinary recording.
It is preferable that the jet section selecting means is arranged so that when the recording medium is fed more than the ordinary amount in the second direction, the number of the jet sections selected in the second area is increased in accordance with the excess of feed amount and the jet sections selected in the areas other than the second area are fixed (not changed, i.e., the same jet sections as those of the ordinary printing are selected). In contrast, when the recording medium is fed less than the ordinary amount in the second direction, the number of the jet sections selected in the third area is reduced in accordance with the shortage of feed amount and the jet sections selected in the areas other than the third area are fixed (not changed, i.e., the same jet sections as those of the ordinary printing are selected).
With the arrangement, since the number of the jet sections selected in the second area is increased in accordance with the excess of feed amount and the jet sections selected in the areas other than the second area are fixed, when the recording medium is fed more than the ordinary amount in the second direction, it is possible to carry out the recording in the next line with the same recording width (in the second direction) as the ordinary one the width.
Similarly, since the number of the jet sections selected in the third area is reduced in accordance with the shortage of feed amount and the jet sections selected in the areas other than the third area are fixed, when the recording medium is fed less than the ordinary amount in the second direction, it is possible to carry out the recording in the next line with the same recording width (the width in the second direction) as the ordinary one.
Namely, it is ensurely possible to avoid the inadequate recording without damaging the quality of the recording even when it continuously occurs that the feed amount is more or less than usual.
It is preferable that the number of the jet sections in each of the first and second areas is 10 percent of that in the third area.
With the arrangement, each of the first and second areas has the jet sections whose number is 10 percent of that in the third area. Upon completion of the recording in 1 line, the recording medium is fed in the second direction, and then stops so as to record the information based on a stopping instruction. Note that it takes a little for the recording medium to stop since such a stopping instruction is entered. More specifically, the recording medium stops after the recording medium is fed in accordance with the inertia. The feed amount of the recording medium in the second direction due to the inertia is about 10 percent of the number of the jet sections in the third area. The jet sections in the first and second are selected in the foregoing manner, taking the inertia into consideration. Thus, the number of the jet sections in the first and second areas is limited, thereby enabling to reduce the cost and to simplify the structure of the apparatus as a whole because it is not necessary to provide any excessive jet sections.
It is preferable that the feed means is composed of a feed roller and its idler roller, and the feed amount detection means detects the feed amount in accordance with the amount of revolution of the feed roller or the idler roller.
In this case, when the feed roller and its idler roller rotate, the recording medium is fed in the second direction in accordance with the revolution of the rollers. The feed amount detection means detects the feed amount of the recording medium in the second direction in accordance with the amount of revolution of the feed roller or the idler roller. The feed amount of the recording medium in the second direction is found based on the circumference length of the feed roller or the idler roller.
It is preferable that the feed means is composed of pairs of a feed roller and its idler roller, (a) a first pair of feed roller and its idler roller are provided in the vicinity of the recording medium and on the downstream side in the second direction and (b) a second pair of feed roller and its idler roller are provided in the vicinity of the recording medium and on the upstream side in the second direction, respectively, and the respective feed amount are detected by the feed amount detection means in accordance with the revolution of the feed roller or the idler roller of each pair.
In this case, the feed amount of the recording medium in the second direction is found by the calculations. During the feeding, the unevenness of the feeding force may occur due to how the recording medium is caught by the feed rollers and their idler rollers, thereby causing the bending of the recording medium.
In order to meet the deficiency, according to the present invention, in the respective first and second pairs that are provided in the vicinity of the recording medium and on the downstream and upstream sides in the second direction, the respective feed amount are detected in accordance with the revolution of the feed roller or the idler roller of each pair. This allows to detect that the unevenness of the feeding force have occurred. It is possible to detect the feed amount with higher accuracy based on the detected result.
It is preferable that, during the recording of the information corresponding to 1 line, a mark for detecting the feed amount is recorded in a non-record area of the recording medium, and the feed amount detection means detects the feed amount in the second direction based on the mark that has been recorded.
In this case, the feed amount of the recording medium is detected by the feed amount detection means based on the mark that has been recorded in the non-record area. This allows to detect the feed amount of the recording medium without affecting the recorded information in the record area and without any complicated structure. It is preferable that the recording of the mark is carried out with the use of a visualizing agent having a hue that is hard to be recognized. The recording of the mark may be made by the dot recording or the line recording. From a viewpoint of the quality of the recording, the dot recording is more preferable because the dot recording less damages the viewer""s feeling and gives no ugly feeling to the viewer""s.
It is preferable that the mark that has been recorded is detected by detection means provided on the more upstream side than the recording medium in the second direction. This allows to quickly cope with the recording operation in the next line.
It is preferable that the feed amount detection means is provided with (a) an encoder made of a rotor, having slits provided at equal spaces in its periphery, that rotates in accordance with the revolution of the idler roller, and (b) light emitting section and light receiving section that are provided so as to be opposite to each other via the encoder in the vicinity of the periphery.
In this case, the idler roller rotates in accordance with the feed amount of the recording medium. In response thereto, the encoder rotates. The light from the light emitting section is emitted toward the encoder. When the light from the light emitting section is directed toward the slit, the light thus directed goes through the slit and arrives at the light receiving section. In contrast, when the light from the light emitting section is directed toward a part between the slits, the light thus directed is blocked and can not arrive at the light receiving section. This allows the light receiving section to generate pulse signals that vary depending on the revolution of the idler roller. The number of revolution of the idler roller can be detected by counting the pulse number of the pulse signal. Since the circumference length of the idler roller is known, the feed amount of the recording medium that has been fed can be converted (found) based on the number of revolution that has been thus detected.
It is preferable that the jet section selecting means is provided with (1) a first memory means for storing image information that has been read out from an original document, (2) a second memory means for storing record information that is a resultant of an image processing with respect to the image information that has been stored in the first memory means, and (3) a third memory means for storing a resultant, to be sent to the recording means, of removing the record information for maintaining a continuity between information that has been read out previously and information that will be read out next from the record information that has been recorded in the second memory means. The jet section selecting means (a) selects the jet sections in the third area so as to carry out an ordinary amount of recording when the feed amount of the recording medium is ordinary, (b) selects the jet sections in an area bridging between the second and third areas so as to carry out an ordinary amount of recording, then stores image information that has been read out from a broader area of the original document in the first through third memory means and selects all the jet sections in the third area and one part of the jet sections in the second area in accordance with the information that has been recorded in the third memory means for the recording of the recording means, when the feed amount of the recording medium is more than usual, and (c) selects the jet sections in an area bridging between the first and third areas so as to carry out an ordinary amount of recording, then stores information that has been read out from a narrower area of the original document in the first through third memory means and selects the jet sections on the first area side in the third area in accordance with the information that has been recorded in the third memory means for the recording of the recording means, when the feed amount of the recording medium is less than usual.
In this case, the original document is read out and the resultant image information is stored in the first memory means. The image information that has been stored in the first memory means is transmitted to the second memory means. The image information thus transmitted is subjected to the image processing, and the resultant of the image processing is stored as record information in the second memory means. The resultant of removing, the record information for maintaining the continuity between information that has been read out previously and information that will be read out next, from the record information that has been stored in the second memory means is stored in the third memory means. The information that has been stored in the third memory means is recorded on the recording medium via the recording means. Thus, the record information for maintaining the continuity between information that has been read out previously and information that will be read out next is remained in the second memory means, thereby ensuring to maintain the continuity of the information to be recorded on the recording medium.
When the feed amount of the recording medium is ordinary, all the jet sections in the third area are selected, the information that has been stored in the third memory means is transmitted to the recording means, and the ordinary amount of recording is carried out via the jet sections thus selected.
When the feed amount of the recording medium is more than usual, the jet sections in an area bridging between the second and third areas are selected so as to carry out the ordinary amount of recording. Then, the image information is read out from a broader area of the original document, and is stored in the first through third memory means in their respective forms. This causes the first through third memory means to have more amount of information than usual stored. All the jet sections in the third area and one part of the jet sections in the second area are selected in accordance with the information that has been recorded in the third memory means so that the recording means carry out the recording. This allows that all the jet sections in the third area are selected so as to carry out the next recording in an ordinary manner. Accordingly, it can be avoided that the excess of the feed amount is not accumulated in the succeeding recordings.
When the feed amount of the recording medium is less than usual, the jet sections in an area bridging between the first and third areas are selected so as to carry out the ordinary amount of recording. Then, the image information is read out from a narrower area of the original document, and is stored in the first through third memory means in their respective forms. This causes the first through third memory means to have less amount of information than usual stored. The jet sections on the first area side in the third area in accordance with the information that has been recorded are selected in the third memory means so that the recording means carry out the recording. This allows that all the jet sections in the third area are selected so as to carry out the next recording in an ordinary manner. Accordingly, it can be avoided that the shortage of the feed amount is accumulated in the succeeding recordings.
As is clear from the foregoing description, even when the recording medium is fed more or less than usual, the continuity of the image information is maintained, the defect and overlapping of the image information do not occur, and it is possible to provide an apparatus with compact and low cost. Further, even when inadequate sheet feedings occur during the recording of a single recording medium, the inadequate sheet feedings are not accumulated, thereby ensuring to remarkably improve the quality of the recording.
The first through third memory means having a small recording capacity are used in considerations of factors such as (a) the size and cost of the apparatus and (b) the fact that the serial recording causes not to cover the large record area by a single scanning. According to the present invention, as has been described above, it is possible to effectively use such memory means having a small recording capacity.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention.